Glutamate is the main excitatory neurotransmitter in the human brain.
It is released by neurons at synapses and binds to several receptor types on the receiving cell. These include AMPA and NMDA receptors, which help produce excitatory postsynaptic potentials. Glutamate is especially important for rapid communication between neurons.
Glutamate also contributes to learning and memory through synaptic plasticity, including long-term potentiation. However, too much glutamate activity can damage neurons, a process called excitotoxicity. This is why the brain tightly controls glutamate release, receptor activity, and removal from synapses.
A common mix-up is confusing glutamate with GABA. Glutamate is generally excitatory in the central nervous system, whereas GABA is the main inhibitory neurotransmitter in the adult brain. Glutamate is also different from monosodium glutamate, the food additive, although both involve the same chemical compound.